The present invention relates to methods for increasing gas production from a subterranean formation. More particularly, the present invention relates to the treatment of a subterranean formation with a cationic polyorganosiloxane comprising at least two quaternary ammonium groups to reduce water blocks in the treated portion of the formation.
Hydrocarbon gases (e.g., natural gas) are found in subterranean formations beneath the Earth's surface. To obtain these gases, well bores are drilled into the gas-bearing formations through which the gas is produced to the surface. Gas production rates from these formations, however, are often less than expected or desired due to a variety of factors. One common factor for lower gas production rates is the presence of water in the flow channels available for gas flow. This water reduces the effective permeability of the formation to the natural gas and is commonly referred to as “water blocks.”
The source of water contributing to the water blocks generally depends on the location of the water blocks themselves. For example, near well bore water blocks may be due to the invasion of water present in the well bore from well operations or from produced water. This water from the well bore may be imbibed by near well bore permeable zones into the flow channels and, thus, reduce gas production. If the water blocks are present in flow channels away from the well bore, the source of water may be due to the connate water held in permeable formation zones due to high capillary pressure. As this connate water moves toward the well bore with continued gas production, it may become trapped in some permeable zones, such as low permeability zones, thus blocking the flow of the gas. The source of water may also be from reservoir stimulation operations (e.g., matrix acidizing, fracturing, water control treatments with relative permeability modifiers, and the like), in which the injected fluids penetrate into the formation. However, in all these examples, if the natural drainage rates (e.g., due to gravity) or induced drainage rates (e.g., due to gas pressure) for the water are low, the water blocks will typically remain in the gas flow channels. As a result, the water blocks will reduce, or in some instances completely shut off, the production of gas from the formation. In some instances, water blocks may even delay gas production for a significant period of time after stimulation treatments.